This invention relates to textile spinning frames or similar machines having spindle assemblies upon whose lower portions yarn underwindings are formed preparatory to the formation of yarn packages upon the upper portions of the assemblies. The invention more specifically relates to an improved method and means for effecting clearance or removal of the yarn underwindings from the lower portions of the spindle assemblies once the underwindings have performed their intended function.
As employed herein, the term "yarn" is intended to encompass all manner of textile strands, whether formed of fibers, filaments or combinations thereof.
In accordance with a well-known mode of operation of a textile spinning frame or like machine, a plurality (e.g., three to five) of wraps or "underwindings" of yarn are formed about the lower portion of each spindle assembly of the machine upon completion of each cycle of package building operation of the machine. The underwindings serve to maintain continuous yarn "thread-lines" to the spindle assemblies while the completed yarn packages are doffed from the assemblies' upper portions and empty bobbins or the like are donned thereon. Upon start-up of the machine, then ensuing upward movement of its ring rails and resumed rotation of its spindle assemblies upwardly displaces the yarn "thread-lines" from the underwound lower portions of the assemblies, and thus the formation of new yarn packages upon the upper portions of the assemblies is automatically initiated. After the foregoing has occurred, the yarn underwindings upon the assemblies are superfluous. However, at each spindle assembly a length of yarn continues to interconnect the yarn underwindings upon its lower portion and the yarn package undergoing formation upon the upper portion of the assembly. Unless somehow earlier removed, such underwindings will therefore remain upon the lower portions of the spindle assemblies throughout the then transpiring package-building operation of the textile machine, and also during the following period when a new series of yarn underwindings are formed upon the lower portions of the spindle assemblies. This and each subsequent series of yarn underwindings overlies and thus secures in place the underwindings already present upon the lower portions of the spindle assemblies. Accumulations of underwindings therefore tend to "grow" upon the spindle assemblies. Since accumulations of excessive size will in various ways impede the operation of the textile machine, "clearance" or removal of the underwindings from the lower portions of the spindle assemblies must eventually be effected in some manner.
One known way of achieving the foregoing result is by a machine operator periodically manually applying an abrading tool, such as a rasp or stiff wire brush, to the yarn underwindings upon the lower portion of each rotating spindle assembly of the textile machines for which such operator is responsible. This procedure is hazardous, tedious and time-consuming, as a consequence of which it may be readily "overlooked" by an operator and, even if actually performed, is expensive from the viewpoint of labor cost. Additionally, the application of abrading forces so shreads or disintegrates the yarn underwindings as to create large quantities of undesirable air-borne fibers or "fly", and will in time also mar or otherwise adversely affect the surfaces of the lower portions of the spindle assemblies.
Another manual technique sometimes employed is for an operator to cut away the accumulated underwindings, by the use of a knife or other cutting tool, upon the lower portions of the spindle assemblies. This procedure is also tedious and time consuming and, moreover, can be safely performed only when the textile machines are not operating. It is therefore expensive from the viewpoint of lost production time, as well as from the labor cost viewpoint.
In recognition of the deficiencies of purely-manual techniques, various automated or semi-automated mechanisms have heretofore been proposed for removing or assisting in the removal of yarn underwindings from the spindle assemblies of textile machines of the types in question. Illustrative prior-art mechanisms are disclosed in U.S. Pat. Nos. 3,782,094, 3,631,663, 3,539,714, 3,426,518, 3,339,356, 3,312,051, 3,263,407 and 2,932,149. Of the foregoing prior-art patents, U.S. Pat. No. 2,932,149 is particularly noteworthy. Such patent discloses a mechanism actuable during each package-building cycle of operation of a textile machine for effecting separation of the length of yarn extending from the single series of yarn underwindings (referred to as "curls" in the patent) then present upon the lower portion of each spindle assembly of the machine, and interconnecting such underwindings with the yarn package then undergoing formation upon the assembly's upper portion. The patent correctly states that after the foregoing length of innerconnecting yarn is separated, the yarn underwindings upon the lower portion of each spindle assembly will usually be automatically cast-off the assembly under the impetus of the latter's continued rotation and the wind-resistance upon the then free "tail" of the underwindings. The aforesaid mode of effecting removal of the yarn underwindings does not necessitate the application of abrading forces to either the spindle assemblies or to the yarn underwindings thereon. It therefore does not damage the spindle assemblies and also, when performed in an optimum manner, permits ready waste-collection of the cast-off underwindings in virtually intact and unentangled condition.
While the mechanism of U.S. Pat. No. 2,932,149 is superior to many other underwinding clearers of the prior art, the yarn separating components which it employs are so constructed and positioned that the underwindings could readily become entangled thereon or cut into smaller lengths while being cast-off from the rotating spindle assemblies. Additionally, the mechanism does not readily lend itself to rapid and low-cost installation, particularly on a "retrofit" basis, to spinning frames or similar textile machines of differing designs and constructions. The mechanism also apparently effects separation of the interconnecting lengths of yarn substantially simultaneously at all of the many spindle assemblies of the textile machine upon which it is installed. Simultaneous separation of the interconnecting lengths of yarn may be effected without detrimental consequences under certain conditions, such as when the yarn undergoing processing is of a relatively "weak" construction. However, when the yarn undergoing processing is relatively strong, as by reason of its size, twist and/or fibrous composition, the attempted simultaneous separation of the interconnecting yarn lengths at each of the many spindle assemblies of the textile machine imposes a significant drag force or additional load upon the whirl-belt drive mechanism customarily employed in a textile machine of the type in question to impart rotative movement to its spindle assemblies. This in turn may cause a significant reduction in the speed of rotation at which the spindle assemblies are driven. Such result is particularly likely to ensue when the drive mechanism is of the type employing a so-called "tangential" belt drive and when yarn separation is achieved by a breaking rather than a cutting action. In any case it is highly undesirable since reduction in the speed of spindle rotation causes the yarn then undergoing processing to receive a lesser degree of twist, and thus to be of inferior quality.
Other prior patents of possible relevence to the present invention, although not pertaining to clearance of yarn underwindings from textile spindle assemblies, include the following: U.S. Pat. Nos. 3,429,745, 3,498,039, 3,540,200, 3,626,680, 3,638,412, 3,651,628, 3,672,143, 3,673,780, 3,712,040, 3,726,072, 3,728,852 and 3,899,868.